1. Field of the Invention
The present invention relates to a cooling system and method for cooling a heat producing system.
2. Background Art
Vehicles today are under an ever increasing demand to do more in less space. For example, an engine in a large commercial vehicle will typically provide torque to power the vehicle, and will also provide power to a variety of vehicle subsystems. Some of these subsystems may be driven directly by the engine through a mechanical link, while others may be operated by electrical power received from a generator, which itself is connected to the engine. As the number of these vehicle subsystems increases, so too does the demand on the engine. Therefore, there is a need to ensure an adequate cooling system for the engine so that it does not overheat or cause damage to vehicle components in close proximately to it. In addition, increasingly stringent emissions requirements can place additional demands on an engine cooling system, as the overall thermal output of the engine is closely managed to help meet the emissions requirements.
The increasing number of requirements placed on engines can be the cause of increased size and complexity of the engine and its subsystems, including its thermal management system. This is at a time when there is a push toward smaller packaging to reduce vehicle size and weight and further increase fuel economy. Of course, many of these same concerns are present in other heat producing systems, for example a fuel cell or an engine used to drive an electrical generator, just to name two. In addition, other systems within a vehicle—i.e., systems other than the engine—may also require thermal management, further increasing the size and complexity of the thermal management system.
One example of a fan control system and method used for heat dissipation is described in U.S. Pat. No. 6,463,891 issued to Algrain et al. on Oct. 15, 2002. Algrain et al. discusses the use of a dual fan system, where the fans supply cooling air to a number of different heat exchangers. The various heat exchangers are used to cool different systems which may have different cooling needs. One limitation of the system described in Algrain et al., is that each fan moves air through more than one heat exchanger. At any given time, the system associated with one heat exchanger may require cooling, while the system associated with a second heat exchanger may not require cooling, and yet both these heat exchangers are fed by the same fan.
This is similar to the heat exchanger described in U.S. Pat. No. 5,992,514 issued to Sugimoto et al. on Nov. 30, 1999. Sugimoto et al. describes a single heat exchanger having several exchanging portions; however, a single fan is used to simultaneously cool all the portions of the heat exchanger. Like the system described in Algrain et al., the system described in Sugimoto et al. lacks a means to individually control each portion of the heat exchanger separately. This can lead to over cooling systems serviced by one portion of the heat exchanger, and undercooling systems serviced by another portion of the heat exchanger.
Therefore, it would be desirable to save space by utilizing a single heat exchanger in a cooling system that could be used to cool a variety of different heat producing systems. Such a heat exchanger would have different cooling zones that could be dedicated to individual heat producing systems, and would also have one or more fans associated with each cooling zone that could supply cooling air to each zone independently of air supplied to the other cooling zones.